Diazinium compounds and diazotype material therefrom



3,539,347 DIAZONIUM COMPOUNDS AND DIAZOTYPE MATERIAL THEREFROM Herbert Rauhut, Wiesbaden-Biebrich, Germany, assignor, by mesne assignments, to Keutrel & Esser Company, Hoboken, NJ.

No Drawing. Continuation-impart of application Ser. No. 711,194, Mar. 7, 1968. This application Apr. 24, 1968, Ser. No. 723,931 Claims priority, application Germany, Mar. 8, 1967,

US. Cl. 96-91 11 Claims ABSTRACT OF THE DISCLOSURE One or two-component diazotype materials of particularly high coupling speed and light sensitivity are provided through the use of a light-sensitive diazonium compound derived from unilaterally diazotized p-phenylene diamine bearing fluorinated alkoxy substituents on the benzene nucleus. The fluorinated alkoxy group is efiec tive in increasing copuling speed when it is situated in any of the 2-, 5-, or 6-position on the benzene nucleus and exhibits a particular effect in increasing light sensitivity .when in the position ortho to the diazo group.

RELATED APPLICATION The present application is a continuation-in-part of application Ser. No. 711,194, filed Mar. 7, 1968, now abandoned, entitled Diazotype Material.

BACKGROUND OF THE INVENTION It is known to use as light-sensitive substances in photoprinting materials, benzene diazonium compounds carrying in 4-position to the diazo group a tertiary amino group which is substituted by alkyl or aralkyl groups or whose nitrogen atom is a component of a heterocyclic radical. These compounds may contain further substituents at the benzene ring, e.g., alkyl or alkoxy groups, preferably in 2- or 5-position to the diazo group.

The properties which render these compounds suitable for diazotype purposes are largely determined by these substituents.

Thus, the light-sensitivity is considerably increased by the presence of an alkoxy group in S-position to the diazo group, while the same group, when in 2-position, de creases the light-sensitivity, but improves the thermic stability of the compound concerned.

A combination of one alkoxy group each in the 2- and in the 5-position of the benzene ring which results in highly light-sensitive and at the same time stable diazonium compounds, has proved particularly suitable for practical purposes. The light-sensitivity may also be influenced by the type of the tertiary amino group in the 4- position. It is increased, e.g., by the presence of a pyrrolidino radical in this position.

The radicals attached to the nitrogen atom affect mainly the coupling speed of the diazo compounds. Lower alkyl groups cause a lower coupling speed than do those with longer carbon chains or aralkyl groups. Heterocyclic radicals instead of a tertiary amino group with aliphatic radicals also normally cause an increase in the coupling speed, but there are wide differences in this respect, e.g., between the readily coupling morpholino compounds and the relatively slow-coupling pyrrolidino compounds. As a further possibility of increasing the coupling speed, the carbon chains of the alkoxy groups in the benzene nucleus may be extended. The readily coupling compounds are used mainly for one-component materials, while the United States Patent 0 See less rapidly coupling compounds are used for two-component materials.

1It has been recognized that the coupling speed of highly light-sensitive photoprinting materials is not sufficient for certain purposes. Thus, for processing two-component materials, photoprinting apparatus are available which are equipped with powerful light-sources which render it possible to use relatively short exposure times. When development, e.g., ammonia development, is to be effected in the same apparatus, the working speed applied for exposure canot be retained for the development step, because in this case the disproportionately low coupling speed requires a longer dwell of the material in the development chamber of the apparatus. Nor is it possible to balance this drawback simply by using a more active coupling component, because this would mean an undue restriction of the choice of color shades available. This drawback is particularly evident in the case of materials with transparent supports, e.g., plastic films of lacquered transparent papers, because the necessary quantities of water vapor and ammonia penetrate less easily into the surface of these materials than into that of normal photoprinting papers.

Also in the case of one-component diazotype materials, it is desirable to use diazo compounds of greater coupling speed. With such materials, it is particularly desirable to replace the alkaline developer solutions normally used hitherto with solutions having a neutral or weakly acid reaction, because such solutions are considerably more stable than alkaline solutions. However, the coupling reaction proceeds considerably more slowly at lower pH-values, so that the choice of highly active diazo compounds available for this purpose is very limited.

SUMMARY OF THE INVENTION It is the object of the present invention to provide diazo compounds which possess a higher coupling speed than the hitherto known compounds, while maintaining a high degree of light-sensitivity.

The invention employs a diazotype material with a light-sensitive one-or two-component layer containing a light-sensitive diazonium compound which is derived from unilaterally diazotized p-phenylene diamine. According to the present invention, a material is provided which contains as the light-sensitive compound a diazonium compound corresponding to the general formula:

where in R and R stand for unsubstituted or substituted alkyl, aralkyl or cycloalkyl groups, or form an unsubstituted or substituted heterocyclic radical with the nitrogen atom,

R stands for hydrogen, an alkoxy group, or a fiuorinated alkoxy group,

R and R stand for hydrogen, halogen, alkyl, alkoxy, or

fiuorinated alkoxy groups, and

X is the anion of the diazonium group,

and wherein at least one of the radicals R and R is hydrogen, and at least one of the radicals R R and R is a fluorinated alkoxy group.

The diazonium compounds of the present invention are distinguished by a coupling speed which is considerably 3 higher than that of compounds containing unsubstituted alkoxy groups instead of fiuorinated alkoxy groups. The coupling speed increases about equally when one of the groups R R or R is the fluorinated alkoxy group. Compounds having two fluorinated alkoxy groups possess an even higher coupling activity. The light sensitivity of the compounds with fluorinated alkoxy groups corresponds approximately to that of the corresponding compounds having unsubstituted alkoxy groups; it is, however, surprisingly increased when a fluorinated alkoxy group is in o-position to the diazo group.

DESCRIPTION OF THE INVENTION Normally, the fluorinated alkoxy radicals have not more than 5 carbon atoms, because the compounds become too difiicultly soluble or surface-active with longer carbon fluoride chains.

All other substituents to the nucleus and the nitrogen atom are known from the diazotype art and their effects have been described. Generally, the alkyl radicals in the tertiary amino group are such as have no more than 5 carbon atoms, and the radicals may contain further substituents in known manner, e.g., halides, hydroxy or amino groups, etc., or straight or branched chains. Normally, the cycloalkyl and arakyl groups contain not more than carbon atoms, benzyl and substituted benzyl groups or cyclohexyl and substituted cyclohexyl groups being preferred. When R and R form a heterocyclic radical with the tertiary nitrogen atom, this radical may be derived in known manner, e.g., from pyrrolidine, piperidine, piperazine, N-methyl-piperazine, thiomorpholine, morpholine, Z-methylmorpholine, 2,6-dimethyl-morpholine, hexamethyleneimine, etc.

When R and R are alkyl groups, they contain normally not more than 2 carbon atoms, methyl groups being preferred. The substituents at the benzene nucleus may also be the alkoxy radicals frequently used in the diazotype art. These radicals, which may carry further substituents, such as hydroxy groups, may contain up to about 5 carbon atoms in a straight or branched chain; methoxy, ethoxy, isopropoxy, n-butoxy, isobutoxy, hydroxyethoxy, ethoxyethoxy groups are exemplary.

The new diazonium compounds provided in accordance with the present invention are separated in the normal manner in the form of their stable double salts or complex salts. Their compatibility with the usual stabilizers and other additives, such as citric acid, sulfosalicylic acid, thiourea, naphthalcne-1,3-trisulfonic acid, zinc chloride etc., is good.

Paper, transparent paper, transparentized paper, cellulose ester films and plastic films capable of being sensitized with diazo compositions may be used as supports in the normal manner.

The new compounds may be prepared analogously to known processes by one of the following procedures:

(A) l-chloro-2-nitro-4-alkoxybenzene is reacted in a polar solvent and in the presence of an alkali with a fluorinated alcohol, e.g., with 2,2,2-trifluoro ethanol, 3,3,2,2- tetrafluoro propanol, or 5,5,4,4,3,3,2,2-octafluoro pentanol. The nitrohydroquinone diether thus obtained is reduced, diazotized, and then converted by the method of Sandmeyer into the corresponding chlorine compound. After nitration in p-position to the chlorine atom, this compound is then reacted with secondary amines, preferably with heterocyclic bases. Examples of suitable heterocyclic bases are: pyrrolidine, morpholine, piperidine, piperazine, thiomorpholine, and the substitution products thereof. The basically substituted nitrohydroquinone ethers thus produced are reduced and then converted in the usual manner into the corresponding diazonium compounds. I

(B) 2,S-dichloro-nitrobenzene is reacted with a fluorinated alcohol in the presence of an alkali to produce the corresponding chloronitrophenyl-fluoroalkyl eth which is nitrated after reduction and alkylation or aralkylation of the primary amino group. After reduction of the nit'ro group, the 4-chloro-5-nitro-2-tert. amino-phenyl-fiuoralkyl ether thus obtained is converted into the diazonium compound.

(C) 3-chloro-4-nitro aniline is reacted with a fluorinated alcohol in the presence of an alkali to yield the corresponding nitroaminophenyl-fluoroalkyl ether, which is then converted into the corresponding diazonium compound after alkylation or aralkylation and reduction.

These methods of preparation are only mentioned as examples. They are preferred at present for the sake of simplicity, because the fiuorinated alcohols used, such as 2,2,2-trifluoro ethanol; 3,3,2,2-tetrafluoro propanol; or 2, 2,2-trifluoro-1,l-dimethylethanol are commercially available. In principle, the new diazonium compounds, such as those represented in the accompanying table, may also be prepared by other methods, e.g., by reacting appropriately substituted phenolates with fluorinated alkyl bromides or alkyl iodides or with fiuorinated sulfonic acid or p-toluenesulfonic acid alkyl esters and processing further in the manner outlined above.

PREFERRED EMBODIMENTS Example 1 A photoprinting base paper normally used for diazotype purposes which was provided on one surface with a precoat of colloidal silica and polyvinyl acetate, was coated on the precoated side with an aqueous solution containing, per 100 ml. of solution:

4.0 g. of citric acid 5.0 g. of thiourea 4.0 g. of the sodium salt of naphthalene-l,3, 6-trisulfonic acid 4.0 g. of zinc chloride 1.4 g. of 2-hydroxy-3-naphthoic acid-(3'-morpholinopropyl)-amide, in the form of the hydrochloride 1.5 g. of the diazonium compound derived from l-amino 4-pyrrolidino-2-methoxy-5-(2',2,2 trifluoro ethoxy)- benzene, in the form of the zinc chloride double salt and then dried.

The finished photoprinting material was image-Wise exposed under an original and developed with ammonia. Images of a neutral blue were obtained on a clear white background.

With this material, the full shades of the blue image were formed within a shorter time of development than with an identical material which contained, however, the zinc chloride double salt of the 4-pyrrolidino-2,5- diethoxy-benzene diazonium chloride as the diazonium compound. Moreover, in the case of the latter comparison material, the background in the image-free areas was yellowish and not a clear white.

Example 2 A polyester film coated with a cellulose acetate lacquer was coated with a solution of the following composition and dried:

20 ml. of water 60 ml. of isopropanol 2 g. of sulfosalicylic acid 1 g. of thiourea 2 g. of 3-hydroxy-4-methyl-phenyl-urea 5 ml. of formic acid 3 g. of the diazonium compound derived from l-amino- 4 morpholino-Z-methoxy-S-(2',2,2-trifluoroethoxy)- benzene, in the form of the zinc chloride double salt.

After image-wise exposure of the finished material under an original and development with gaseous am monia, yellow images of good actinic opacity were obtained, while the image-free areas showed good transparency.

Equally good images were obtained when the diazonium compound mentioned above was replaced by the same quantity of the diazonium compound derived from 1- amino 4 morpholino-2-(2',2',2'-trifluoroethoxy)-5-methoxybenzene, in the form of the zinc chloride double 6 Brown images of good contrast were obtained on a white background. 7

The full color shade produced by coupling was obtained immediately after application of the developer.

salt, and the materials produced possesses a distinctly 5 Example 4 hi her light-sensitivit When the above-mintioned diazonium compounds were A photopnntmg base paper, the kmd customaflly replaced by the same quantity of the diazonium used for diazotype purposes with a precoat of colloidal pound derived from 1-amino-4-piperidino-2-methoxy-5- 1O Sihca d polyvinyl acetate W q the precoated (2',2.',2'-trifiubroethoxy)-benzene, in the form of the slde i aqueous solutlon contammg P 100 zinc chloride double salt, the results obtained were of of Solunon' equal quality. As compared with the first-mentioned materials, the color shade of this material had a slightly cltl'lc redder tint 4.0 g of the sodium salt of naphthalene-1,3,6-tr1sulfon1c As compared with a material which has been prepared acld and according to the same recipe, but with the known diazoof the dlazonlum p d r I-amm nium compound from 1-amino-4-morpholino-2,5-dieth- (N yl)' oxy-benzene, in the form of the Zinc chloride double trlfluoroethoxy)benzene: the form of the tetfafluosalt, the final point of coupling was reached distinctly borateearlier with the material according to the invention. The d d d v actinic opacity of the material according to the invention an me was also distinctly better. The fimshed photoprmtlng material was lmage-wlse exposed under a transparent original and then developed EXample 3 with a solution which contained, per 100 ml. of solution: A photoprinting base paper customarily used for diazotype purposes which was provided on one surface with 0330 phlorQgluclPol a precoat of colloidal silica and polyvinyl acetate, was 9-600 of ms?dlum curate coated on the precoated side with an aqueous solution g k fg which contained, per 100 ml. of solution: 5:700 8 z gz i fgg ride a d 0.60 g. of tartaric acid 0.200 g. of the sodium salt of a dialkyl-naphthalene- 3.00 g. of the sodium salt of naphthalene-1,3,6-trisulfonic sulfonic acid acid 0.02 g. of saponine, and and had a pH-value of about 6.

1.50 g. of the diazonium compound derived from l-amino- Black images on a white background formed shortly 4 dimethylamino 6-chloro-5-.(2',2',2'-trifiuoroethoxy)- after application of the developer. benzene, in the form of the zinc chloride double salt, Equally good lt were bt i d h th b mentioned diazonium compound was replaced by the and then m diazonium compound derived from l-amino-4-(N-methyl- The fimshed photoprinting material was image-wise N benzyl) amino 3 a tran.sp.arent Ongmal and fleveloped propoxy)-benzene and the above procedure was folwith a solution contalnmg, per 100 ml. of solut1on: lowed 2.5 g. of borax The black color shade-which appeared black even in 3.0 g. of soda the continuous tones-was formed within a still shorter 2.0 g. of sodium chloride time when the diazonium compounds mentioned above 5.0 g. of thiourea were replaced in the above prescription by 2.0 g. of the 0.1 g. of the sodium salt of isopropyl-naphthalene-sulfonic diazonium compound derived from 1-amino-4-[N-(2- acid acetyloxyethyl) N-benzyl] amino-2-chloro-5-(2,2',2-

0.6 g. of resorcinol, and trifluoroethoxy)-'benzene and the same procedure was 0.6 g. of phloroglucinol. followed.

TABLE Melting point of corresponding nltrocom- R1 R2 R3 R4 R5 pound O.

CH3 CH3 o-om-om 01 H 8990 CH CH O-CH -CF H 01 108 CgH CgHs H O-CHa-CFs H 68 CH; CH Q O-CHz-CFa 01 H 102-103 CH3 CHaQ OCH2CF: O-OHa H 84 CQH4-CO-CH3 CHZQ O-CHz-CF3 C]. H 83 CH; CH Q O-CH CFzCHFz 01 H 98 OCH:CF3 O-CHa H 143 TABLE-Continued Melting point of corresponding nitrocom- R1 R R3 R4 R5 po und C.

N O-GHa OCHzCFa H 134 N O-CHn-CF2 OCH2CF3 H 112 N OCH: OCHZCF2CHF2 H 148-149 N OCHzCFs 0CH3 H 138 N O-GHa-CFa OCH3 H 87 N O-CHa-CF; Cl H 126 The above examples have been presented for the purpose of illustration and should not be taken to limit the scope of the present invention. -It will be apparent that the described examples are capable of many variations and modifications which are likewise to be included within the scope of the present invention as set forth in the appended claims.

What is claimed is:

1. A light-sensitive diazonium compound of the general formula:

wherein R is an alkyl group having 1-5 carbon atoms or an aralkyl group, R is an alkyl group having 1-5 carbon atoms, or R and R together form a saturated 5, 6 or 7 membered heterocyclic radical with the nitrogen atom,

R is a hydrogen, an alkoxy group having l-S carbon atoms, or an alkoxy group having fluorine substitution to the carbon atoms of the alkoxy group wherein the alkoxy group has 1-5 carbon atoms,

R; is a hydrogen, a halogen, an alkoxy group having 1-5 carbon atoms, or an alkoxy group having fluorine substitution to the carbon atom of the alkoxy group wherein the alkoxy group has 1-5 carbon atoms and R is a hydrogen or a halogen, and

X is the anion of the diazonium compound,

and wherein at least one of the radicals R and R is hydrogen and at least one of the radicals R or R is an alkoxy group having flourine substitution to the carbon atoms of the alkoxy group.

2. Diazotype material comprising a support and a light-sensitive composition coated thereon, said composition comprising a diazonium compound according to claim 1.

3. Diazotype material according to claim 2 having an azo dye coupler compound capable of forming an azo dye with said diazonium compound in the light-sensitive composition.

4. Diazotype material according to claim 2 wherein said compound is a zinc chloride double salt of a 4-dimethylamino 6 chloro-S-(2',2,2-trifluoroethoxy)-benzene diazonium compound.

5. 'Diazotype material according to claim 2 wherein said compound is a tetrafluoborate salt of a 4-(N-methyl- N benzyl) amino-2-chloro-5-(2',2',2'-trifluoroethoxy)- benzene diazonium compound.

6. Diazotype material according to claim 2 wherein said compound is a tetrafluoborate salt of a 4-(N-methyl- N benzyl) amino 2 chloro-5-(3',3,2,2'-tetrafiuoropropoxy)-benzene diazonium compound.

7. Diazotype material according to claim 2 wherein said compound is a tetrafiuoborate salt of a 4-[N-(2'- acetyloxyethyl)-N-benzyl]-amino-2-chloro 5 (2',2,2'- trifluoroethoxy)-benzene diazonium compound.

8. Diazotype material according to claim 3 wherein said compound is a zinc chloride double salt of a 4-pyrrolidino 2-n1ethoxy-5-(2',2 ,2-trifluoroethoxy) -benzene diazonium compound.

9. Diazotype material according to claim 3 wherein said compound is a zinc chloride double salt of a 4- morpholino-Z-methoxy-S-(2',2,2'-trifiuoroethoxy) benzene diazonium compound.

10. Diazotype material according to claim 3 wherein said compound is a zinc chloride double salt of a 4- morpholino-2- 2',2',2'-trifiuoroethoxy -5-methoxy benzene diazonium compound.

11. Diazotype material according to claim 3 wherein said compound is a zinc chloride double salt of a 4-piperidino-Z-methoxy-S-(2,2',2-trifluoroethoxy) benzene diazonium compound.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 5 NORMAN G. TORCHIN, Primary Examiner Kessels 9649 Sanders et a1 C. L. BOWERS, IR., Assistant Examlner Printy et a1. 9691 XR Hendrickx et a1. 9691 Rauhut et a1. 260-141 XR 10 260-441;

Eonshuistra et a1. 9649 

